The present invention relates to an image display apparatus, in particular, a thin image display apparatus such as a flat panel display and an image display method therefor.
Conventionally, a liquid crystal display apparatus (LCD) has been widely used as an image display apparatus of an information terminal device, such as a personal computer or a personal digital assistant (PDA), or a car navigation system. The liquid crystal display apparatus has advantages such as a high response speed and an ability to display clear color moving images, although it also has disadvantages such as a complicated structure and a high production cost resulting in a high product price, a high power consumption, necessity of supplying electric power for image holding, a narrow viewing angle, and the like. Therefore, image display apparatuses adopting various systems are proposed as alternatives to the liquid crystal display apparatus.
For instance, a display apparatus is proposed, which performs switching between ON and OFF of an image by utilizing a liquid film boiling phenomenon (see JP 05-127603 A and JP 05-127604 A, for instance). Also, a display apparatus is proposed which loads/unloads ink in a cell into/from an image display portion through thermal expansion/shrinkage of the ink or mechanical driving or a diaphragm, thereby performing switching between ON and OFF of an image (see JP 2001-42794 A, for instance). Further, a display apparatus is proposed which adopts a system where approximately one-half of lightproof fluid is sealed in a translucent enclosure (cell) partially covered with a light shielding mask and switching between light transmission and light shielding is performed by driving the lightproof fluid using a gradient of the surface tension of the lightproof fluid caused through irradiation of infrared rays from outside (see JP 2002-169105 A, for instance).
In the case of the image display apparatus disclosed in JP 05-127603 A and JP 05-127604 A described above which utilizes the fluid film boiling phenomenon, however, the duration of the film boiling is as short as 10 μsec, so there is a problem in that in order to continue to display an image, it is required to continue to apply a voltage of around 10 kHz. Aside from this, there are various problems in that the durability of the apparatus is low and the chromas of displayed images are low and the like.
Also, in the case of the system disclosed in JP 2001-42794 A described above which utilizes thermal expansion and shrinkage of the ink, the thermal expansion coefficient of the ink is low, so even if the ink is heated to a temperature of from 300 K to 350 K, the volume change of the ink is as small as about 2%. Therefore, in order to ensure a predetermined volume increase, a reservoir tank that is considerably large with respect to the volume of the image display portion is required, which leads to a problem in that the size of the apparatus becomes larger. Also, in the case of the system based on the diaphragm mechanical driving, there is a problem in that the structure of the apparatus becomes complicated, which inhibits miniaturization of the apparatus. Further, in the case of the system disclosed in JP 2002-169105 A described above, light with a specific wavelength is blocked by the light shielding mask, so there occurs a problem in that once information is written by causing the lightproof fluid to move, it is impossible to refresh the written information.